Russia has violated a four-year-old agreement with the U.S. by flying armed jets over a U.S. garrison in Syria nearly every day this month, according to Lt. Gen. Alexus Grynkewich, who is in charge of air operations in the area....The U.S. has more than 900 troops, and hundreds more contractors, in Syria, working with Kurdish fighters to quell any resurgence of the Islamic State, which was defeated as a caliphate in 2019. Russia's military has been backing Syrian dictator Bashar al-Assad during his country's 12-year-old civil war....Grynkewich said Russia might be trying to put more pressure on the U.S. military...